1. Field of the Invention
Embodiments of the present invention generally relate to gate valves for vacuum chambers, more specifically, slit valves for use in the semiconductor processing industry.
2. Description of the Related Art
Integrated process tools are often used in the semiconductor processing industry to rapidly expose a single substrate to many chemical and mechanical processes. These processes are performed in multiple chambers that are connected by additional transport, storage, and temperature and pressure adjustment chambers. To isolate the chambers during substrate processing, specialized gate valves are used. The gate valves are designed to operate in low pressure and harsh processing conditions and to provide enough of a transfer area to accommodate the substrate support robot or other mechanism that moves a substrate through slits in an integrated processing tool. Gate valves are often designed to reduce friction between components and to reduce formation of contaminating particles.
The slit valves can be designed to reduce friction using sequential vertical and horizontal motion in a fixed, predetermined path. Such valves often utilize cam and slide mechanisms and multiple shafts to place the valve in a closed position. Alternatively, the valve surfaces may travel in a housing and may also contact the housing to provide sufficient force to seal the slit.
The use of contact surfaces and multiple shaft support mechanisms results in additional friction areas that will increase the likelihood of particle generation in the system. Thus, further reducing particle generation can be achieved by improving slit valve design.